Alas Babylon

When I was in high school I read a book that I liked so well it stays with me. It is/was a book that dealt with nuclear war. It was about a guy whose brother is in the military and high enough up to know when things are looking bad. The brother determines that the man lives in an area where he is unlikely to be eliminated by a nuclear attack. The brother asks him to take in his family if it looks like things are going to hell. He won't be able to tell him what's happening, but he will let him know by saying in their conversation "Alas Babylon". The fits and starts of these people rebuilding their lives seemed very well thought out to a teenager.

These warnings brings this story to my mind. I'm not sure how much I'll prepare. I find it difficult to consider logically.